Multiple spot photomedical treatment using a laser indirect ophthalmoscope

ABSTRACT

A laser indirect ophthalmoscope (LIO) apparatus for photomedical treatment and/or diagnosis is presented. The LIO apparatus allows multiple spot ophthalmic surgery to be performed in a wider range of patient positions and less intrusively than currently available methods. The LIO apparatus utilizes a separate or integral beam multiplier that generates one or more optical beams via spatial and/or temporal separation, and an optical system that conditions and directs the one or more optical beams to a target to form a pattern. The LIO apparatus includes a headset, and is therefore wearable by the user (e.g., a physician).

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of priority under 35 U.S.C. §119(e)of U.S. Ser. No. 60/737,548, filed on Nov. 16, 2005, the entire contentof which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to patterned photothermaltreatment of retinal tissue and particularly to such treatment using alaser indirect ophthalmoscope.

BACKGROUND INFORMATION

Conditions such as diabetic retinopathy and age-related maculardegeneration are subject to photocoagulative treatment with laser light.While this type of laser light treatment slows the damage rate of theunderlying disease, it has its set of problems. For example, because thetreatment entails exposing the eye to a large number of laser lightpulses for a long period of time (typically each pulse is on the orderof 100 ms), damage can be caused to the patient's sensory retina fromthe heat that is generated. During the treatment, heat is generatedpredominantly in the retinal pigmented epithelium (RPE), which is themelanin-containing layer of the retina directly beneath thephotoreceptors of the sensory retina. Although visible light ispredominantly absorbed in the RPE, this type of treatment irreversiblydamages the overlying sensory retina and negatively affects thepatient's vision.

A slit-lamp-mounted laser delivery device is commonly used for this typeof laser light treatment. In this device, the slit lamp is arranged toallow easy illumination and microscopic viewing of the eye of a seatedpatient. Slit lamps used in laser treatment/surgery include ahigh-brightness illuminator and microscope assemblies mounted on ashared pivot point. This arrangement allows the viewing angle of themicroscope and illuminator to be changed as often as desired withoutmoving the field of illumination or visualization transversely.

Slit-lamp-mounted laser delivery devices have their shortcomings.Specifically, certain parts of the eye are difficult to treat with thistype of device. For example, the anterior aspect of a retinal break isby far the most important part to seal, as this is the area mostsubjected to vitreous traction. However, this area is not completelyaccessible with a slit-lamp-delivered laser system. Also, theslit-lamp-mounted laser delivery device is not well suited for treatingsmall infants or bed-ridden patients. Furthermore, it is difficult toorient the patient's head position with slit-lamp-mounted systems. Thus,these devices have limited ability to treat patients with detachedretinas and other conditions where gas or dense fluids have beenintroduced into the eye to secure detached tissues prior to laserexposure. To treat these conditions, the patient's head is oriented toreposition the tissue or tamponade material.

FIG. 1 shows a Laser Indirect Ophthalmoscope (LIO), which may be used inconjunction with the slit-lamp-mounted laser delivery device to overcomethese shortcomings. As illustrated, the LIO 1 is worn on the physician'shead using a headset 2 and is used to treat peripheral retinaldisorders, particularly in infants or adults requiring treatment in thesupine position. It is typically used in an operating room or clinicalenvironment. Traditionally, an LIO 1 is used with a fiber optic coupledlight source 3 attached to a beam delivery and visualization system 4via an optical fiber 5, which is worn by a physician, to delivertreatment spots one at a time, with the physician moving his or her headand/or the ophthalmic lens to reposition the aiming beam prior todelivering another spot of treatment light. This is difficult andtiresome for both patient and physician.

Accordingly, there is a need for a flexible and time-efficient approachto retinal photocoagulation with an LIO that is not provided by knownmethods or apparatus.

SUMMARY OF THE INVENTION

The present invention is an improved device and method for patternedphotothermal treatment of retinal tissue utilizing a laser indirectophthalmoscope.

An apparatus for photomedical treatment or diagnosis of a target tissueincludes a light source for generating light, a headset designed to beworn by a user wherein the headset includes an input for receiving thelight and an output for projecting the light on a target tissue, and abeam multiplier positioned for receiving the light and for generatingone or more optical beams by spatial and/or temporal separation of thelight for projection thereof via the output on the target tissue in theform of a pattern.

A method of treating target tissue includes generating light, conveyingthe light to a head mountable LIO apparatus having an input forreceiving the light and an output, converting the light to one or moreoptical beams in the form of a pattern using a beam multiplier thatspatially and/or temporally separates the light, and projecting thepattern of the one or more optical beams to target tissue.

Other objects and features of the present invention will become apparentby a review of the specification, claims and appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional Laser Indirect Ophthalmoscope (LIO).

FIG. 2 shows a conventional slit-lamp delivery device.

FIG. 3 is a schematic diagram of a photomedical system using a beammultiplier in accordance with a first embodiment of the invention.

FIGS. 4A through 4I illustrate examples of laser spot patterns that canbe generated by the photomedical system of the invention.

FIGS. 5, 6, 7, 8, 9, 10, 11, 12, 13, and 14 are a schematic diagrams ofa first, second, third, fourth, fifth, sixth, seventh, eighth, ninth,and tenth embodiments of the beam multiplier BM.

FIG. 15 is a second embodiment of the photomedical system using a fiberbundle to deliver multiple spots.

FIG. 16 is a third embodiment of the photomedical system whereby thefiber unit is a fiber bundle.

FIG. 17 is a fourth embodiment of the photomedical system whereby thefiber unit contains a fiber multiplier.

FIG. 18 shows a 2×2 fiber arrangement can be adjusted to change the spotpattern size and spacing.

FIGS. 19A through 19G show exemplary shapes of the spots that may beformed with the photomedical system.

FIG. 20 is a fifth embodiment of the photomedical system using ananamorphic element AC.

FIGS. 21 and 22 are a schematic representation of the photomedicalsystem 100 illustrating the LIO apparatus.

DETAILED DESCRIPTION OF THE INVENTION

Multiple spot laser therapy is known. For example, U.S. Pat. No.4,884,884 by Reis discloses “beam multiplication” by various means. U.S.Pat. No. 5,921,981 by Bahmanyar and Jones discloses a slit-lamp baseddelivery device and intraocular probes only for multiple spottreatments. U.S. Pat. Nos. 6,066,128; and 6,096,028 by the sameinventors cover only intraocular probes. However, multiple spot lasertherapy is limited in application because it is performed utilizingslit-lamp delivery device (shown in FIG. 2), which has the disadvantagesdescribed above. An alternative way of performing multiple spot lasertherapy is to utilize probes that are inserted into the eye. However,the use of probes is undesirable because of their intrusiveness.

This invention is based on multiple spot laser therapy using a LaserIndirect Ophthalmoscope (LIO). Using the LIO allows multiple spot lasertherapy to be performed without intrusive probe insertions. Moreover,because the LIO allows the physician to treat patients in the supineposition, the invention adds flexibility to multiple spot laser therapy.

FIG. 3 is a schematic diagram of a photomedical system 100 in accordancewith a first embodiment of the invention. The photomedical system 100,which may be used for photomedical treatment or diagnosis, includes aCPU 12, an electronic input/output device 14, a light generation unit15, and an LIO apparatus 16. The light generation unit 15 is opticallycoupled to the LIO apparatus 16 by a fiber unit 42. A user, such as aphysician, wears the LIO apparatus 16 to view a target with his/her eye34 through an ophthalmic lens 19. In this case, the target is the retinaof an eye 1 (i.e., the patient's eye). The user 34 may see the eye 1directly or through a screen, such as graphical user interface 36. TheCPU 12 is coupled to the light generation unit 15 to control lightgeneration. Optionally, the CPU 12 also controls the LIO apparatus 16.The CPU 12 may be a microprocessor, microcontroller, or any other typeof suitable control electronics.

The light generation unit 15 includes a light source 10. The lightsource 10 may be a diode-pumped solid state laser, gaseous laser,semiconductor laser, light emitting diode, flash lamp, etc. The lightsource 10 is controlled by the CPU 12 via the input and output (I/O)device 14 to create an optical beam 11, whose centerline is shown bydashed lines. The optical beam 11, upon being generated by the lightsource 10, encounters mirror M1 which directs a first portion of theoptical beam 11 to a photodiode PD1. The photodiode PD1 may be replacedwith other types of sensors, as appropriate. The photodiode PD1 servesto sample and measure the power of the light for safety purposes. Asecond portion of the light from the mirror M1 that is not directed tothe photodiode PD1 goes to a shutter S, which acts as a gate to theoptical beam 11. The shutter S controls the optical beam 11 to producediscrete spots or a continuous supply of the optical beam to createcontinuous scans as a means to produce the desired pattern. If theshutter S blocks the light, the optical beam 11 does not travel further.On the other hand, if the shutter S lets the light pass, the opticalbeam 11 goes on to mirror M2 and mirror M3. Mirror M2 is a turningmirror that may be used in conjunction with mirror M3 to align theoptical beam 11 into the fiber unit 42.

Multiple spot laser therapy may be performed using an optional aimingbeam in addition to a treatment beam. The aiming beam is used toindicate the location of the beam on the target tissue 1. It may becoincident upon the treatment beam, or provide an outline (or otherindication) of the area to be treated. Where an aiming beam is used inaddition to the treatment beam, the optical beam 11 generated by thelight source 10 is the treatment beam, and a separate aiming beam isproduced by an aiming light source 17. The aiming light source 17preferably produces light of a different wavelength than the lightsource 10. Once the treatment beam is aligned with the aiming beam, thetreatment beam is delivered for treatment of the eye. Each of the aimingbeam and the treatment beam may include a single spot of light, multiplediscrete spots, or continuous pattern(s) of light.

The aiming beam and the optical beam may be interleaved by gating thelight beams on and off. Each spot of light may be round or have someother shape. The aiming beam and the treatment beam do not need to beproduced simultaneously. Mirror M3 combines the aiming beam with theoptical beam 11 and directs the combined light into the fiber unit 42via the lens L1. The lens L1 is used to inject the optical beam 11 intothe optical fiber unit 42.

Although use of an aiming beam is contemplated as an option, thedescription herein will focus on the optical beam 11 for simplicity ofillustration. Where an aiming beam is used, the optical beam 11 that isreceived by optical fiber unit 42 is a combination of the aiming beamand the treatment beam.

If the light source 10 produces visible (or otherwise aim quality)light, it may also be used for producing the alignment pattern, making aseparate aiming light source 17 unnecessary. The alignment patterncoincides with portions of the eye 1 that will later be illuminated withthe optical beam 11 and ensures that the system is properly aligned tothe target portion(s) of the eye 1.

The optical beam 11 is transmitted to the LIO assembly 16 via an opticalfiber unit 42. A pattern generator assembly 18, where lens L2 acts asthe optical input for receiving the optical beam, and mirror M4 acts asthe optical output for projecting the beam onto the target tissue, inthe LIO apparatus 16 receives the optical beam 11 and directs theoptical beam 11 toward the target—i.e., the retina R of the patient'seye 1. The optical beam 11 is focused on the eye 1 and perceived by thepatient. A pattern (which may be predetermined) is disposed at thepatient's retina R. The position and character of the pattern may becontrolled by use of an input device 20 (e.g., a remote control panel)or other user interface, such as graphical user interface (GUI) 36. Aperson of ordinary skill in the art would understand that thedisposition of the optical beam 11 is a function of the optics of thephotomedical system 100 and any particular conditions of the patient.Particular conditions that may affect the ultimate disposition of theoptical beam 11 include cataracts, retinal inhomogeneities, andintraocular debris, among others.

Lenses L2, L3, and L4 of the pattern generator assembly 18 function tocondition and direct the optical beam 11 to the patient's eye 1. Lightexiting the optical fiber unit 42 first encounters lens L2 and becomes,for example, collimated before entering the lens L3. Lens L3 may be asingle lens or a compound lens, and can be configured as a zoom lens foradjusting the intrinsic size of the beam that comprises the pattern. Thelight coming out of the lens L3 passes through the beam multiplier BMand enters the lens L4. The beam multiplier BM produces a pattern ofmultiple spots or a scanned pattern.

When the mirror M4 is small, it may be placed directly in thevisualization path 33 without much disturbance. Mirror M4 may also beplaced in the center of a binocular imaging apparatus withoutsubstantially disturbing the visualization. Lens L4 could also be placedone focal length away from the optical midpoint of the scanning opticsto produce a telecentric scan, such as is required for optimalperformance by certain choices of ophthalmic lens 19. In this case, themirror M4 would need to be large enough to contain the entire scan, andcould be made as a high reflector spectrally matched to the output oflight sources 10 and 17, if used. Visualization 34 of the target zone ofthe eye is accomplished by viewing through the mirror M4. A furtherrefinement would be to white balance the transmission of mirror M4,making it photopically neutral, by using a more complicated opticalcoating that makes the transmitted image appear more natural ratherthan, for example, pinkish when using a green notch filter coating onmirror M4 as would be required when light source 10 produces greenlight. Visualization system 98 is contained in the LIO assembly 16, andallows the user to visualize the retina R of patient eye 1, preferablywith both eyes of the user.

In some embodiments, the CPU 12 also controls the movement of mirror M4thus controlling the location of the beam/pattern on the target tissue1. The optical scan to form the pattern can be created in a number ofdifferent ways, such as by moving the light source 10, moving the mirrorM4, using one or more rotating wedges, using acousto-optic deflector(s),or galvanometric scanner(s), etc. Preferably, mirror M4 may be rotatedas already described, or in the case of a mirror with surface curvature(optical power), it may also be translated to produce optical deviation.In the case where mirror M4 has optical power, compensating opticalelements (not shown) may be required to produce an image, as opposed tosimple illumination as shown. The perception of both discrete spots andspot blinking may be accomplished by scanning quickly between elementsof the pattern so as to limit the amount of light registered by thepatient and observed in those intermediate spaces.

The pattern may also be used to fixate the patient so that the patientlooks at a fixed position away from the optical axis of the physician'svisualization and light delivery system, thereby keeping the patient'seye still, and also providing the physician direct optical access to theretinal periphery. Small motions of the pattern may be used to minimizeactual eye movement while still capturing the patient's attention. Thistechnique may be especially useful in situations such as pan retinallaser photocoagulation treatment where slight eye movement can betolerated. Slightly moving the pattern about a center position toattract the patient's attention makes it easy for the patient to fixateon the pattern. Ensuring fixation is especially important duringprocedures such as macular grid laser photocoagulation treatment, whereunintended laser exposure to the central vision is to be avoided.

The ophthalmic lens 19 aids in the user 34 visualization of the retinaand creates a magnified intermediate image of retina R at location IP.The ophthalmic lens 19 may then serve to help relay the beam/pattern toretina R. The beam thus relayed to the target tissue 1 will be magnifiedby the inverse of the image magnification of ophthalmic lens 19. Theophthalmic lens 19 may be a contact or non-contact lens, and may also beused in conjunction with the lens L4 to provide for conjugate pupilplanes such that the scanning pivots about the patient's iris, thusmaximizing the system's retinal scan field.

FIGS. 4A through 4I illustrate examples of laser spot patterns that canbe generated by the photomedical system of the invention. The spots in apattern are of equal irradiance, size, and separation. FIGS. 4A, 4B, and4C show linear arrays (e.g., 2×1, 3×1, 4×1) and FIGS. 4D through 4I showtwo-dimensional arrays (e.g., 2×2, 3×2, 4×2, 3×3, 4×3 and 4×4). Otherpatterns may also be generated, such as a circular pattern that may beused to encircle retinal tears. The edge-to-edge separation distancebetween spots typically varies from 0.5-3 times the spot diameter. Forexample, a separation distance of 0.5 times the spot diameter may beused for encircling retinal tears, while a separation distance of 3times the spot diameter may be used for treating lattice degeneration.

There are different ways the beam multiplier BM may produce multiplespots. One way of producing multiple spots is to employ the beammultiplier BM in the LIO assembly 16 as shown in FIG. 3. The LIOassembly 16 is worn by the user 34 (e.g., physician, surgeon) usingconventional head mounting hardware. The beam multiplier BM may containactive and/or passive components. The beam multiplier BM may or may notbe controlled by the CPU 12 (e.g., a passive element such as adiffractive optic could be used). Thus, in FIG. 3, the connectionbetween the beam multiplier BM and the system is shown with dashedlines. The beam multiplier may be changed or adjusted to alter the spotpattern and/or the orientation of the pattern. The beam multiplier BMmay be rotated to re-orient the pattern. This may be performedautomatically via CPU 12. Additional optics may also be used to rotatethe pattern orientation, such as a Dove prism, not shown. Alternately,beam multiplier BM may be incorporated into the light generation unit15, and delivered to the pattern generator assembly 18.

The beam may be multiplied simultaneously, scanned to ultimately producea pattern of delivered spots, or both. Thus, as used herein, “beammultiplication” by beam multiplier BM applies to simultaneous beammultiplication (e.g., by dividing a beam into multiple sub-beams—spatialseparation), beam scanning (e.g., beam spots or pattern are projected orformed sequentially—temporal separation), or any combination of the two.FIGS. 5, 6, 7, and 12 show embodiments of the beam multiplier BM thatgenerates the pattern primarily by scanning. FIGS. 8, 9, 10, 11, 13, and14 show embodiments of the beam multiplier BM that generates a patternprimarily by dividing a beam into multiple sub-beams. FIGS. 15, 16, and17 show embodiments of the photomedical system 100 that generate thepattern using multiple fibers connected to the light generation unit 15.FIG. 20 shows an embodiment of the photomedical system 100 thatanamorphically generates the pattern. In FIGS. 5-14, the lens L3 is notalways explicitly shown; however, a person of ordinary skill in the artwill understand that the lens L3 may sometimes be needed for adjustingthe ultimate size of the optical beam on the target tissue.

FIG. 5 is a schematic diagram of a first embodiment of the beammultiplier BM. In this embodiment, the beam multiplier BM is made withactive components such as one or more mirror-based galvanometricscanners. This first embodiment includes a pair of orthogonal axisgalvanometric scanners 64 a, 64 b. The lens L2 conditions optical beam11 prior to its incidence upon the first scanner 64 a, which directs theoptical beam 11 toward the second scanner 64 b. As the scanner 64 amoves, it reflects the optical beam 11 in different directions. Beamsthat are reflected in different directions strike the second scanner 64b at different locations, and are reflected by the second orthogonalaxis scanner 64 b onto different locations on the lens L4. Lens 66 mayserve to further condition the beam exiting the scanners, for example,for the purpose of aberration control, but is not necessarily required.The beams reach the lens L4 at different locations and angles. In thecase of a telecentric scan, where the midpoint between the scanners 64 aand 64 b is located nominally one focal length away from lens L4, thebeams reach the mirror M4 at different points and are reflected towardthe image of the target tissue provided by ophthalmic lens 19 as shownin FIG. 3. When the timing of the laser pulses is coordinated with theangular position of the mirrors of the scanners 64 a and 64 b, separatebeams (i.e., multiple spots) are created. However, if the light source10 were left to run continuously, a likewise continuous pattern may becreated.

FIG. 6 is a schematic diagram of a second embodiment of the beammultiplier BM. In this embodiment, the beam multiplier BM includes anoptical element with focusing power, specifically an off-axis movinglens 68 that is movable transversely to the optical axis and able torotate eccentrically (i.e. not about its optical axis). As the lens 68spins, the optical beam 11 coming from the lens L2 reaches differentparts of the lens 68, thus getting refracted differently depending onwhat portion of the lens 68 is encountered. The lens L4 directs theoptical beam 11 coming from different angles emanating from lens 68 todifferent spots on the mirror M4. The lens 68 may be replaced with amirror in other embodiments, where different portions of the moving lens68 would reflect the beam at different angles.

FIG. 7 is a schematic diagram of a third embodiment of the beammultiplier BM. In this embodiment, the beam multiplier BM includes arotating reflective polygon scanner 70 and a reflective element 72. Therotating polygon 70 may be configured to provide different deviationangles on different facets. As the polygon rotates about an axis 71, theoptical beam 11 coming from the lens L2 hits different points on thepolygon 70 and leaves the polygon 70 at different angles. The reflectiveelement 72 receives the optical beam 11 from the polygon 70 and directsit to the lens L4. The lens L4 forwards the optical beam 11 to themirror M4. The position on the mirror M4 that the optical beam 11strikes differs depending on which part of the polygon 70 reflects theoptical beam 11.

FIGS. 8 and 9 are schematic diagrams of fourth and fifth embodiments ofthe beam multiplier BM, respectively. The fourth and fifth embodimentsutilize diffraction elements. In FIG. 8, the beam multiplier BM includesa transmissive diffraction element 74, which could be an acousto-opticdeflector, hologram, a grating, a phase array, or an adaptive optic, forexample. The optical beam 11 coming from the lens L2 reaches thetransmissive diffraction element 74 and gets divided into sub-beams 11a, 11 b which strike the mirror M4 in different places, and/or atdifferent incident angles.

In FIG. 9, the beam multiplier BM includes a reflective diffractionelement 76 along with reflective elements 78. The optical beam 11 comingfrom the lens L2 reaches the reflective diffraction element 76 to getdivided into sub-beams 11 a, 11 b. The reflected sub-beams 11 a, 11 bare redirected toward the lens L4 by one of the reflective elements 78.Eventually, the sub-beams 11 a, 11 b strike the mirror M4 and propagatetoward the eye 1 along separate paths.

Using diffractive or refractive elements to deviate the beam yieldsdifferent results for different wavelengths. This sensitivity towavelength complicates the use of a different-colored aiming beam andmulti-spectral treatment sources. Thus, when more than one wavelength isused, such as in the case of FIG. 9, another dispersive element may beused to compensate for the difference in results. An adaptive optic mayalso be used to directly create matching patterns for treatment andaiming light by rewriting its configuration for each wavelength. Such adevice would also allow for the straightforward adjustment of thepattern, provide simultaneous and/or sequential beam multiplication, andeven be made to also focus the beam(s). A lens array or a diffractiveoptical element placed in the optical system provides a plurality ofsimultaneous spots.

FIGS. 10 and 11 are schematic diagrams of a sixth and seventhembodiments of the beam multiplier BM, respectively. The sixth andseventh embodiments utilize transmissive and reflective diffractiveelements with dispersion compensation. The embodiment of FIG. 10 issubstantially similar to the embodiment of FIG. 8, with the addition ofa dispersion compensating element(s) 80. The embodiment of FIG. 11 issubstantially similar to the embodiment of FIG. 9, with the addition ofdispersion compensating elements 82. The dispersion compensatingelements 80, 82 may be high dispersion prisms or tilted plates, such asthose made from flint glasses or plastics.

The components described in FIGS. 5 through 11 may be used in anycombination not explicitly shown here.

FIG. 12 is a schematic diagram of an eighth embodiment of the beammultiplier BM, whereby the beam multiplier BM includes a prism 84. Theprism 84 rotates (as shown by the arrow) so that the optical beam 11coming from the lens L2 strikes at a different incident angle on theprism 84 and experiences a different degree of refraction depending onhow it strikes the prism 84. The prism may also be made to rotate aboutthe optical centerline of the system to create 2-dimensional patterns.The optical beam 11 that is refracted passes through the lens L4 toreach the mirror M4.

FIG. 13 and FIG. 14 show ninth and tenth embodiments of the beammultiplier BM utilizing reflective elements. In FIG. 13, the beammultiplier BM includes 2 beamsplitters 86 and a mirror 88. The opticalbeam 11 reaches the first beamsplitter 86, which directs a fraction ⅓ ofthe optical beam 11 to the mirror M4 and allows the remaining portion ofthe optical beam 11 to pass to the second beamsplitter 86. The secondbeamsplitter 86 then directs a fraction ½ of the beam it received towardthe mirror M4. The remaining optical beam 11 is reflected toward themirror M4 by the mirror 88. Although n=3 in the example of FIG. 13 thatproduces a 3×1 array pattern, this is not a limitation of the inventionand n may be any integer that produces the pattern. To equallydistribute the optical power amongst the spots of the pattern, thereflectivity of an individual beamsplitter 86, R_(i), in an array ofm=n−1 beamsplitters 86, is given by the relation, R_(i)=(m−i+2)⁻¹, wherei is the number of the individual beamsplitter in the array, startingwith i=1 for that nearest incoming light. Of course, in thisconfiguration the reflectivity of the last beamsplitter will always be50%. Lens L2 may serve to collimate the beam, thus allowing for theelements of the pattern to be focused onto a plane at the target by asubsequent lens, such as lens L4 shown in FIGS. 3, 5-12.

FIG. 14 shows an embodiment of the beam multiplier BM wherein thebeamsplitters 86 and the mirrors 88 are arranged to produce atwo-dimensional array pattern. In this embodiment, n=4 although this isnot a limitation of the invention. The optical beam 11 reaches the firstbeamsplitter 86, which directs about ¼ of the optical beam 11 to themirror M4 and passes the remaining portion of the optical beam 11 to thesecond beamsplitter 86. The second beamsplitter 86 directs another ¼ ofthe optical beam 11 to the mirror M4. The remaining ½ of the opticalbeam 11 gets reflected off two mirrors 88 to travel in a direction thatis the opposite of the original direction in which the optical beam 11entered the beam multiplier BM and is out of the plane of theillustration of FIG. 14. For simplicity, the illustration of FIG. 14 isdepicted in one plane. Traveling in this reverse direction, the opticalbeam 11 encounters one more beamsplitter 86, which directs about ¼ ofthe original optical beam 11 to the mirror M4 and finally another mirror88. The result is a 2×2 matrix pattern. Many such possibilities existfor creating other patterns. Again, here the same relation describedabove holds for R_(i).

FIG. 15 is a second embodiment of the photomedical system 100 whereby abundle of optical fibers 42 is used to deliver multiple spotssequentially. A fiber bundle that has its individual fibers separated atthe input end can have a scanner positioned prior to fiber input suchthat it will direct the optical beam 11 to an individual fiber alone,ultimately providing a sequential pattern of spots by switching betweenthe individual fibers. Alternately, the fiber bundle 42 may have morethan a single fiber illuminated at a time to produce groupings ofsimultaneous spots. Sequential scanning of such simultaneous spots isalso possible. The scanning element 30 (e.g., galvo mounted mirror(s))is used to direct light to a single fiber of the bundle at any giventime. The scanning element 30 may be spaced about one focal length awayfrom lens L1 to provide for a telecentric scan condition, thus allowingfor the injection of light into all the fibers to be on parallel pathsand preserving the launch numerical aperture across the bundle. Such abundle, or array, of fibers may be made to have its constituent fiber'sinput ends lie along a line for simplified single axis scanning (asshown), or be a 2-dimensional array accessed using a 2-dimensionalscanner. The positions of the output ends of the fibers of the fiberbundle ultimately define the pattern.

FIG. 16 shows a third embodiment of the photomedical system 100 wherebya fiber bundle 42 is used to deliver multiple spots simultaneously. Theoptical beam 11 leaving the light generation unit 15 fills theindividual fibers in the bundle simultaneously. Light output from thisfiber bundle 42 will provide a pattern of simultaneous spots onto targettissue 1. The optical system of pattern generator assembly 18 may bemade to image the face of the fiber bundle onto the target tissue (sayvia the intermediate image created by ophthalmic lens 19).

FIG. 17 is a fourth embodiment of the photomedical system 100 where asingle fiber is used with a fiber multiplier as part of the fiber unitto provide delivery of multiple spots. A passive fiber splitter may beused to distribute light into multiple fibers simultaneously, or anactive fiber switch may be used to sequentially vary which fiberconducts the light. This fiber multiplier is labeled “FM” and shown withdashed lines connecting it to the CPU 12. The output ends of theindividual fibers are distributed prior to lens L2. This distributionmay be maintained in the final disposition of the spots on the targettissue.

FIG. 18 shows an example of how a 2×2 fiber multiplier FM can beadjusted to change the spot pattern size and spacing. In FIG. 18, wedges90 are driven in and out to achieve different fiber spacing. Thedelivered pattern is moved or altered as a result of the wedges 90 beingdriven in and out. Similarly, a single conical element may be driveninto the center of the fiber output array, thus varying the spacinguniformly with only a single adjustment.

The device of the invention allows the treatment time to be reduced by afactor that is approximately equal to the number of pulses delivered,whether the pulses are delivered simultaneously or sequentially.Simultaneous delivery has the advantage of being faster than sequentialdelivery, but requires a light source capable of delivering n times theoutput power, wherein n is the number of elements in the pattern.Sequential delivery, while being slower than simultaneous delivery,places less demand on the power of the light source and providesflexible adjustment of the ultimate delivery pattern. Both simultaneousand sequential deliveries with the device of the invention significantlyreduce the treatment time and the placement precision of the lesionswhen compared to the manual technique that is conventional today. Theeye can be considered stationary for approximately one second, the“fixation time.” The number of spots that can be delivered sequentiallyin this fixation time is inversely proportional to their pulse duration.

FIGS. 19A through 19G show exemplary shapes of the spots that may beformed with the photomedical system 100. As shown, the shapes includeone or more lines, a rectangle, one or more arcs, or a large arc area.These patterns/shapes may be generated, for example, by scanning acontinuous beam or providing a beam-shaping device such as an adjustableaperture, or adaptive optic such as a liquid crystal matrix, or usinganamorphic optical elements, such as cylindrical lenses, to create thedesired shape instantaneously.

FIG. 20 is a fifth embodiment of the photomedical system 100. In thisembodiment, the beam multiplier BM includes an anamorphic element AC.The anamorphic element AC allows the optical beam 11 to beanamorphically adjusted to provide an immediate beam shape on the targettissue that is different from the beam shape of the original opticalbeam 11. For example, even if the original optical beam 11 would haveproduced a circular spot, the anamorphic element AC is capable ofproducing the shapes shown in FIGS. 19A-19G. Conversely, even if theoriginal optical beam 11 would have produced a non-circular spot, theanamorphic element AC is capable of producing a circular spot. Theanamorphic element AC may be an adaptive, torroidal, or cylindricaloptic. The anamorphic element AC is shown as connected to the CPU 12with a dashed line because it may be either an active or a passivedevice.

FIG. 21 is a schematic representation of the photomedical system 100illustrating the LIO apparatus 16. In the embodiment that is shown, thebeam multiplier BM is contained in a housing that may or may not includethe indirect ophthalmoscope illumination light (not shown). As describedabove, the beam multiplier BM may produce multiple spots eithersimultaneously or sequentially by a number of different means. Thedevice is worn on the head using a headset 92, and the patient's fundus(not shown) is viewed through visualization system 98 (typically abinocular assembly) using the illumination (not shown) provided from theheadset 92. An external light source may also be used for thevisualization illumination. The treatment beam is also provided directlyto the headset 92 via fiber optic connection 42 from the lightgeneration unit 15. Optionally, the light generation unit 15 may alsocontain an aiming light 17 to display where a spot or a pattern of spotswill be ultimately disposed on the target tissue. Alternatively, apattern alignment target 96 (shown here with dotted lines to indicate itas an option) may be used in the optical path of the visualizationsystem 98, and thus only visible to the physician. The pattern alignmenttarget 96 may be made removable or interchangeable to allow fordifferent patterns to be used. Each pattern alignment target 96 wouldneed to be recognized by the system in order for it to provide anaccurate representation of the treatment pattern. The physician mayadjust the ultimate disposition of the beam on the patient's fundus bymoving her head and/or the ophthalmic lens 19.

FIG. 22 is another schematic representation of the photomedical system100 illustrating the LIO apparatus 16. Unlike the LIO apparatus 16 ofFIG. 21, this LIO apparatus 16 shows an embodiment where the fiber unit42 is a bundle of fibers capable of sequential and/or simultaneous spotdelivery. The beam multiplier is not shown in FIG. 22 for simplicity ofillustration, but the device may include or exclude the beam multiplier,as described above.

A “pattern,” as defined herein is meant to include either thesimultaneous or sequential delivery of a plurality of spots, such asthose shown in FIGS. 4A-4I and 19. Likewise, “spots” are herein meant todescribe either illumination with a static beam or a moving (scanned)beam. Each beam need not be round, but may be of any shape. For example,a non-circular cross-section fiber optic may be used in an imagingsystem to provide a beam of the same non-circular cross-section on thetarget tissue. Furthermore, any desired shapes may be createdanamorphically or by scanning the beam, as described above. It should benoted that any of the treatment and/or aiming beam generation andcontrol techniques, and/or any of the beam multiplying and/or scanningtechniques, described herein can be implemented in combination withand/or incorporated as part of the head mounted LIO headset 92 shown inFIGS. 21 and 22.

Although the invention has been described with reference to the aboveexamples, it will be understood that modifications and variations areencompassed within the spirit and scope of the invention. Accordingly,the invention is limited only by the following claims.

1. An apparatus for photomedical treatment or diagnosis of a targettissue, the apparatus comprising: a light source for generating light; aheadset designed to be Worn by a user, wherein the headset includes aninput for receiving the light and an output for projecting the light ona target tissue; a beam multiplier positioned for receiving the lightand for generating one or more optical beams by spatial and/or temporalseparation of the light for projection thereof via the output on thetarget tissue in the form of a pattern.
 2. The apparatus of claim 1,wherein the beam multiplier is supported by the headset.
 3. Theapparatus of claim 2, wherein the beam multiplier is positioned forreceiving the light from the input.
 4. The apparatus of claim 1, whereinthe pattern comprises one or more discrete spots on the target tissue.5. The apparatus of claim 4, wherein each of the discrete spots is astraight or curved line.
 6. The apparatus of claim 3, further comprisinga zooming lens located between the input and the beam multiplier foradjusting a size of the first optical beam.
 7. The apparatus of claim 1,further comprising a zooming lens located after the beam multiplier foradjusting a size of the one or more second optical beams.
 8. Theapparatus of claim 3, further comprising a collimating lens locatedbetween the input and the beam multiplier.
 9. The apparatus of claim 1,wherein the beam multiplier comprises a beam scanner for refracting orreflecting the light, the beam scanner generating the optical beams bytemporal separation of the light.
 10. The apparatus of claim 1, whereinthe beam multiplier comprises: a first scanner for deflecting the lightin a first direction; and a second scanner for deflecting the light in asecond direction perpendicular to the first direction.
 11. The apparatusof claim 1, wherein the beam multiplier comprises a moving lens that ispositioned to refract the light at a different angle depending on thelocation of the moving lens that receives the light.
 12. The apparatusof claim 11, wherein the moving lens spins about an off-center axis. 13.The apparatus of claim 1, wherein the beam multiplier comprises arotating prism that is positioned to refract the light at differentangles depending on an orientation of the prism.
 14. The apparatus ofclaim 1, wherein the beam multiplier generates the optical beams bysimultaneously dividing the light into the optical beams.
 15. Theapparatus of claim 1, wherein the beam multiplier comprises atransmissive diffraction element for converting the light into theoptical beams.
 16. The apparatus of claim 1, wherein the beam multipliercomprises a reflective diffraction element for converting the light intothe optical beams.
 17. The apparatus of claim 1, wherein the beammultiplier comprises a dispersion compensating element.
 18. Theapparatus of claim 1, wherein the beam multiplier comprises a pluralityof beam splitters.
 19. The apparatus of claim 1, wherein the beammultiplier is an adaptive optic.
 20. The apparatus of claim 1, whereinthe beam multiplier comprises an anamorphic correction element.
 21. Theapparatus of claim 20, wherein the anamorphic correction element is anadaptive optic or a cylindrical lens.
 22. The apparatus of claim 1,wherein the beam multiplier comprises: a plurality of optical fibers.23. The apparatus of claim 22, wherein the beam multiplier furthercomprises: a scanning element for sequentially delivering the light toone or more of the plurality of optical fibers.
 24. The apparatus ofclaim 1, wherein the beam multiplier comprises: a first optical fiber; aplurality of optical fibers; and a fiber splitter for receiving thelight from the first optical fiber and directing the light to theplurality of optical fibers.
 25. The apparatus of claim 1, wherein thebeam multiplier comprises: a first optical fiber; a plurality of opticalfibers; and a fiber switch for receiving the light from the firstoptical fiber and sequentially directing the light to the plurality ofoptical fibers.
 26. The apparatus of claim 1, further comprising: acontroller for controlling the light source.
 27. The system of claim 9,wherein the beam multiplier is positioned for generating the opticalbeams by temporal separation such that the second beams are sequentialpulses.
 28. The system of claim 27, wherein the sequential pulses havingdurations no longer than 50 ms.
 29. The system of claim 1, wherein thebeam multiplier comprises an adjustable aperture for creating theoptical beams having a shape that is different from that of the light.30. The system of claim 1, further comprising: a second light source forgenerating an aiming beam that is combined with the light.
 31. Thesystem of claim 22, wherein the fiber multiplier includes means foradjusting a spacing of the fibers.
 32. A method of treating targettissue, comprising: generating light; conveying the light to a headmountable LIO apparatus having an input for receiving the light and anoutput; converting the light to one or more optical beams in the form ofa pattern using a beam multiplier that spatially and/or temporallyseparates the light; and projecting the pattern of the one or moreoptical beams to target tissue.
 33. The method of claim 32, wherein theconverting of the light is performed before the conveying of the light.34. The method of claim 32, wherein the converting of the light isperformed after the conveying of the light.
 35. The method of claim 32,wherein the converting comprises: scanning the light to create thepattern.
 36. The method of claim 35, wherein the pattern comprises oneor more discrete spots on the target.
 37. The method of claim 32,wherein the converting comprises: splitting the light into the opticalbeams for simultaneous impingement of the optical beams on the targettissue.